Various types of boilers are used in different industries, such as steam boilers used for electrical power generation. The boilers may have large, enclosed, metal-lined tanks used for containing water or steam and generally include a converging pair of downwardly sloping lower boiler tank walls. In order to ensure the continued satisfactory performance of boilers, the tanks must be periodically maintained, repaired, and internally cleaned. As a part of the procedure for maintenance, repair or cleaning, it is necessary for workmen to enter inside the boiler tank and work on the inside walls of the boiler. Scaffolding systems having platforms arranged in vertical levels are placed inside a boiler being maintained or cleaned so that workmen are provided with suitable platforms to stand on while working on the inside walls of the boiler. The platforms also provide a location for the placement of tools used in the work performed inside the boiler.
One previous approach used to support scaffolding inside a boiler included scaffolding support bars which were temporarily welded directly onto the lower boiler sidewalls. Scaffolding was then erected inside the boiler with support provided by vertical posts which would rest on the support bars and thus would transfer the weight of the scaffolding directly to the lower boiler sidewalls through weldments. This prior approach was not entirely satisfactory in that the welding was time-consuming and the scaffolding support bars had to be precisely arranged on the lower boiler sidewalls in order to properly support the vertical posts. Also, the locations of the support bars had to be precisely measured and laid out so that the vertical posts of the scaffolding would be properly supported. In this prior approach, after the cleaning or maintenance was completed, the weldments would be broken and the scaffolding support bars would be removed from the boiler sidewalls. The breaking and removing of weldments could damage the boiler walls.
Many and various types of scaffolding systems may be used to support work platforms inside a boiler. One type of scaffolding system is shown by H. S. Evans in U.S. Pat. No. 3,245,188 which shows the use of prefabricated members which can be easily fitted together to provide scaffold structures having a variety of base plans of differing sizes and which are braced at all the joints. In particular, FIG. 11 of that patent shows an adjustable post which may be used in scaffold structures. Similarly, adjustable struts for use in a scaffolding structure are shown by T. I. Gostling in U.S. Pat. No. 3,366,361. The disclosures of the two above-mentioned patents are incorporated herein by reference.